There's a lot of people out there that have quit there jobs for Adsense income.
One of the people that come to mind is Lisa Irby from 2createawebsite.com
It took her awhile though to earn enough with adsense to live off of.
To be honest with you. Relying on Adsense income alone is not a good thing.
Google could ban your account and then you'd have no income at all unless you earn money other ways such as affiliate marketing or selling your own product or service.